RocketRAID 3700 vs. RocketRAID 4500 series – is DV Mode superior for video applications?

Depending on your specific application, yes; DV Mode can help streamline workflows for RAID arrays comprised of SAS/SATA hard disk drives. However, it is only supported by RocketRAID 4500 series 6Gb/s SAS/SATA hardware RAID controllers (PCIe 2.0 x8 host interface).

DV Mode is an innovative, intelligent caching algorithm designed specifically for video applications. The default firmware cache policy provides balanced performance for standard applications such as a general-use workstations, file servers, or web servers. However, DV mode activates unique a cache setting at the firmware level, designed to minimize latency when processing and transferring large files. 

There are several things to consider before using DV Mode:

• Only RocketRAID 4500 series Hardware RAID controllers support DV Mode (RR4522SGL, RR4520SGL).
• DV mode is only available for RAID 0, 5, and 6 arrays
• DV Mode can only be applied to a single RAID array.
• DV Mode requires that the RAID status is “Normal”. It will not function if the array is “Critical” or “Disabled”.
• DV Mode was designed for use with hard disk drives.  It may not provide benefits for SSD-based RAID configurations.

DV Mode can be enabled when creating an array. The WebGUI management interface provides the following options:

Margin

[5% - 25%]

When DV mode is enabled, you have the option of changing the “Margin”.

This percentage represents the amount of space the designated cache will retain before flushing the data onto the drive. Increasing the margin % will result in more stable performance, but will decrease the maximum write performance of the array.

Note: the Margin can be adjusted at any time using the WebGUI. (Click the Logical tab, and then click on the Maintenance option displayed towards the right-hand side of the target array: